Artist’s concept of the ExoMars Trace Gas Orbiter. Credit: ESA/ATG medialabThe ExoMars Trace Gas Orbiter, a Russian-launched, European-built spacecraft that arrived at Mars in October, is starting to dip into the upper reaches of the red planet’s atmosphere in a year-long “aerobraking” campaign place the observatory in the right position to hunt for methane, an indicator of potential biological activity.The effort to reshape the craft’s course around Mars uses aerodynamic drag from repeated dips into the upper atmosphere to gradually drag down the high point of the probe’s orbit from its current altitude of 20,500 miles (33,000 kilometres) to a planned perch 250 miles (400 kilometres) above the Martian surface.Ground controllers at the European Space Operations Centre in Darmstadt, Germany, are overseeing a series of seven thruster burns to nudge the low point of the spacecraft’s orbit from an altitude of 120 miles (200 kilometres) down to 70 miles (113 kilometres).The Trace Gas Orbiter completed the first two burns Wednesday and Saturday, according to Håkan Svedhem, TGO’s project scientist at the European Space Agency. He said the orbit’s low point was at an altitude of 87 miles (140 kilometres), as of Monday.The next orbit-lowering maneuver ...